This next years effort will be concerned, in the main, with determining the types and amounts of lipoteichoic acid being excreted into a defined medium by Streptococcus pyogenes, type 12, and its physiological L-form and, in particular, at what stage of the growth cycle is this excretion maximized for each organism. In addition, the destructive effect of the intra- and extra-cellular lipoteichoic acids from each organism on mouse glomeruli will be quantitatively compared. In addition, concomitant morphological (light and electron microscopy) and biochemical studies will be coordinated in order to determine if (a) biochemical perturbations are detectable long before morphological destruction becomes apparent and, if so, if (b) these microbial lipoteichoic acids specifically affect the synthesis of the glomerular basement membrane. These biochemical studies will utilize radioactively labelled materials and tissue culture techniques and will concentrate on the effect of lipoteichoic acid on the synthesis of collagen by mouse glomeruli.